package com.rd.teacher.jichao.day03;

public class SystemTest {

    public static void main(String[] args) {
//        long current = System.currentTimeMillis();
        // 打印出一些系统和用户信息
//        System.out.println(System.getProperty("java.version"));
//        System.out.println(System.getProperty("os.name"));
//        System.out.println(System.getProperty("os.version"));
//        System.out.println(System.getProperty("user.name"));
//        System.out.println(System.getProperty("user.dir"));
//        for (int i = 0; i < 1000; i++) {
//            System.out.println(i);
//        }
//
//        System.exit(0);
//
//        long time = System.currentTimeMillis() - current;
//        System.out.println(time);

//        System.out.println(System.nanoTime());

        String str = new String("zhangsan");
        System.out.println(str);
        str = null;
        // 触发垃圾回收
        System.gc();
        System.out.println(str);

    }
}
